Enable HiDPI scaling on Windows by default

[einarf]

We should obey the UI scaling on windows by default. This is supported in pyglet 2.1. Users with 4k screens no longer need to look at a postage stamp of a window.

It looks like the scaling in pyglet doesn't work like on MacOS/retina were the window size stays unchanged. Only framebuffer size increases and you get a pixel ratio between them. The plan in pyglet is to support two modes:

• "window_only": you are supposed to scale the content yourself
• "window_and_content": Like MacOS/retina

Related issue: pyglet/pyglet#1202

[pushfoo]

I can't test this at the moment, but I don't see a reason not to merge it. @DragonMoffon or @DigiDuncan, can you try it on one of your systems?

[einarf]

• Can be merged when 2.1.dev6 is out.
• We need to disable scaling for unit tests.

[DragonMoffon]

Pyglet dev6 just released if we want to look into this again

[pushfoo]

I finished #2385:

• type checking / import linting
• tests which occasionally fail (it's mouse position triggering extra mouse enter events)